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I don't know about venting more than one appliance, but we use it all the time. Just make sure it is supported well on horizontal runs otherwise it will sag and we all know that's not good with condensing equipment. It is even easier to use than PVC.

It is not approved for CAT I as B-vent and chimneys are. It shows using it to reline B-vent, which is highly controversial since it was not listed this way. Time will tell. It is listed for CAT II and IV but not III so be careful of your applications.

Anything that vents under positive pressure cannot be common vented with other appliances regardless of what a vent mfr. says. I will talk with Dale Menges in Tech Svcs. this week about this.

It is not approved for CAT I as B-vent and chimneys are. It shows using it to reline B-vent, which is highly controversial since it was not listed this way. Time will tell. It is listed for CAT II and IV but not III so be careful of your applications.

Anything that vents under positive pressure cannot be common vented with other appliances regardless of what a vent mfr. says. I will talk with Dale Menges in Tech Svcs. this week about this.

I actually talked with regional sales about that issue.

Polypro CAN be used for common venting, IF the manufacturer of the appliances allows common venting (commonly known as cascading).

If the appliances you are venting are not approved by the manufacturer for cascading, then you cannot use polypro for cascading.
If the appliance is not approved by the manufacturer for polypro at all, then you cannot use polypro.

This has to do with the liability and certifying. They are approving their pipe for it's usage in general, not for it's usage to specific applications.

hearth can maybe explain it in more technical terms, but basically:

Follow manufacturers recommendations.
If you want to use polypro for a specific appliance, then you need to look at polypro's certification sheet:http://www.duravent.com/docs/product...oApprovals.pdf
There is nothing special about polypro that allows you to do anything different than you would with regular PVC, baring the (vertical only) flexible chase (which is clearly still not seen the end of approvals),

We looked into this as solution for removing 80% water heater/furnaces in stacked condos, and replacing with all 90% equitment if the law were to require it.

"Better tell the sandman to stay away, because we're gonna be workin on this one all night."

"Dude, you need more than 2 wires to a condenser to run a 2 stage heatpump."